There are many devices with two transducers on the market, such as laptops, tablet computer, mobile phones, and smartphones, as well as portable media players or smartphone docking stations and soundbars for TVs. Compared to a conventional stereo system with two discrete loudspeakers, the two transducers of such devices are located in a single cabinet or enclosure and are typically placed very close to each other. Due to the size of these devices, the transducers are usually spaced from each other by only few centimeters.
This results in a narrow sound reproduction, almost “mono-like”. When playing a stereo recording on such devices, all sound sources are perceived as being centered.
Several different solutions have been proposed in order to increase the spatial effect of such systems with small loudspeaker span angles using different concepts.
EP 2 222 092 B1, for example, describes beamforming used in soundbars, with the goal to reflect acoustic beams of sound on walls surrounding the listener in order to achieve a spatial effect. The impression of sound arriving from the right side can be achieved by steering a beam to a position on the right wall where it is reflected and arrives at the listener. While this method can achieve convincing spatial effects, it requires a large number of transducers and relies on regular walls with good reflective properties all around the listener. Furthermore, a calibration of the system is needed to adapt to the room properties.